In a skillet or saucepan, heat your butter over medium. Let cook for about 3-4 minutes until it’s starting to bubble then continue cooking, stirring frequently, until it starts to get foamy, about 3 more minutes. At this point light brown bits will start to form at the bottom of the pan. Keep stirring until your butter is amber in colour and smells nutty and delicious. As soon as it has browned slightly, remove from the heat and pour into a liquid measuring cup. Add miso paste and whisk to combine.

Pour your brown butter into a large bowl with the coconut sugar. Add the egg and vanilla and whisk vigorously for 1-2 minutes to dissolve the sugar. You should have a smooth, glossy mixture.

Add in your flours, baking soda + a big pinch of sea salt and stir to combine. Add the rolled oats and mix to form a dough, then fold in the chocolate chunks (the dough will look wet).

Preheat oven to 350F. While your oven preheats, place cookie dough in the freezer to firm up for about 15 minutes (crucial to the texture!).

Once ready, scoop about 2 tbsp dough per cookie onto a lined baking sheet. Make sure to leave room between each cookie as they will spread.

Bake for 11-12 minutes until edges are lightly browned and cookies are just starting to set in the middle (they will look underbaked). Remove from the oven and gently tap your baking sheet on the counter to get that ripple effect, then use a mug or a round cookie cutter to swirl around each cookie. They spread a lot so this is an important step for the perfect shape and texture!

Sprinkle cookies with flakey sea salt if desired, then let cool completely for at least 30 minutes before serving (they will firm up as they cool). Enjoy!